tdf#138834: fix crash in table creation wizard when clicking next

See bt here:
https://bugs.documentfoundation.org/attachment.cgi?id=168082

Change-Id: Icc89803bd89ce82d4699eef3cfe7892395d0634f
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/107610
Tested-by: Jenkins
Tested-by: Caolán McNamara <caolanm@redhat.com>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
diff --git a/dbaccess/source/ui/control/FieldDescControl.cxx b/dbaccess/source/ui/control/FieldDescControl.cxx
index 8f3854f..525b5a5 100644
--- a/dbaccess/source/ui/control/FieldDescControl.cxx
+++ b/dbaccess/source/ui/control/FieldDescControl.cxx
@@ -78,7 +78,8 @@ OFieldDescControl::OFieldDescControl(weld::Container* pPage, OTableDesignHelpBar
    , m_nEditWidth(50)
    , pActFieldDescr(nullptr)
{
    m_pHelp->connect_focus_out(LINK(this, OFieldDescControl, HelpFocusOut));
    if (m_pHelp)
        m_pHelp->connect_focus_out(LINK(this, OFieldDescControl, HelpFocusOut));
}

OFieldDescControl::~OFieldDescControl()